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  "identifier" : "/documentation/CoreImage/CIFilter-swift.class/exclusionBlendMode()",
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  "title" : "exclusionBlendMode()"
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# exclusionBlendMode()

Subtracts color values to blend colors with less contrast.

```
class func exclusionBlendMode() -> any CIFilter & CICompositeOperation
```

## Return Value

The modified image.

## Discussion

This method applies the exclusion-blend mode filter to an image. The effect calculates the brightness value for both images and subtracts the smaller value, resulting in a darker image.

The exclusion-blend mode filter uses the following properties:

- `inputImage`: An image with the type [`CIImage`](/documentation/CoreImage/CIImage).
- `backgroundImage`: An image with the type [`CIImage`](/documentation/CoreImage/CIImage).

The following code creates a filter that mixes the colors and results in an output image that’s less saturated:

```swift
func exclusionBlendMode(inputImage: CIImage, backgroundImage: CIImage) -> CIImage {
    let colorBlendFilter = CIFilter.exclusionBlendMode()
    colorBlendFilter.inputImage = inputImage
    colorBlendFilter.backgroundImage = backgroundImage
    return colorBlendFilter.outputImage!
}
```

![The image on the top left shows a beach with multiple palm trees and a rainbow arching across the blue sky.  The image below is a gradient image displaying a gradual color shift from purple to a dark orange. The image on the right shows the output from applying an exclusion-blend mode filter. The result displays a blend of colors from both images with a darker contrast.](images/com.apple.coreimage/media-3546411@2x.png)

---

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